When to use bitmap indexes

I understand that bitmap indexes are efficient for columns with a fairly small and static set of values, but am interested in gathering any information that I can on experience with them to help in decision making for a number of cases.

Several cases seem perfect candidates for bitmap indexes -- y/n columns which are often used in queries. But what about a column with 50 values and 100,000 records? What if values would be added every once in a while?

Is it all pretty much trial and error, or can the decision be quantified in any way?

thanks -- Received on Mon Nov 30 1998 - 16:23:04 CST